The present invention generally relates to a cleaning aparatus and to a method of cleaning and, more particularly, to vacuum-type cleaners which apply a cleaning fluid containing a liquid component and a detergent component to the object to be cleaned and which subsequently remove the cleaning fluid together with the entrained contaminants.
Various constructions of cleaning apparatuses for cleaning furniture, rugs and analogous textile material objects are already known. An apparatus of this kind usually includes a cleaning head having an intake opening which is in communication with a suction channel and which is adapted to be juxtaposed with a contaminant-bearing object to be cleaned, and such apparatus often also includes nozzles which spray a pressurized stream of cleaning fluid directly onto the object. However, such an apparatus has the disadvantage that the pressurized stream is directed normally through the plane of the intake opening so that the stream actually tends to force the contaminant or dirt particles contained in the upper regions of the object even deeper into the interstices of the base web. The dirt particles thereby tend to become anchored and accumulate in the fabric material, thus making subsequent cleaning operations necessary. Such additional cleaning operations are disadvantageous because they are costly and increase the wear of the fabric by subjecting the fabric for longer periods of time to higher suction forces which are now required to remove the more deeply embedded dirt, and by more frequently exposing the fabric to the chemical action of the chemical detergent agents.
The prior art also has the disadvantage that the cleaning liquid is applied to an object to be cleaned at points, or in strips when the cleaning head is moving along the objects, i.e, it is applied non-uniformly. In oder to achieve uniform wet cleaning over the whole surface of the respective object, the cleaning head has to be moved several times over the same area of the object.
The prior art also has the disadvantage that, when the cleaning head is lifted from a respective contaminated portion of an object or when the cleaning head is applied only partially to an object, the cleaning fluid tends to drip down onto the object through the intake opening. This situation is evidently disadvantageous and has been heretofore solved only in an unsatisfactory manner by requiring an operator to repeatedly turn off the supply of cleaning fluid prior to lifting the cleaning head from one location and moving the same to another location.
Another cleaning head for cleaning surfaces of carpets includes a suction cap connected to a generator of subatmospheric pressure and also includes a series of nozzles, the outlets of which have small areas and are aimed directly onto the surface of the carpet or onto the plane of application of the cleaning head, which is defined by a rim of the suction cap. The nozzles are connected via a supply duct to an aerated cleaning fluid reservoir, the cleaning fluid leaving the outlets only when drawn out of the same by the subatmospheric pressure that then exists in the suction cap. In this way loss or dripping of the cleaning fluid is avoided, during a partial application of the cleaning head to, or when the cleaning head is lifted from, the carpet. However, disadvantages of this arrangement are that the quantity of fluid that can be emitted by the nozzles per unit of time and hence the depth of penetration of the cleaning fluid into the carpet are limited, and it is practically impossible to work with the cleaning head above the level of fluid in the fluid reservoir, as for example when it is desired to clean curtains, wall coverings or the like. The range of use of the cleaning head is therefore restricted as regards the materials which can be cleaned, and the cleaning effect is also limited. The cleaning of an object is strictly limited to the upper surface regions. Deeply embedded dirt cannot be effectively picked up.